Overview Valproic Acid, Magnesium Sulphate, Rocuronium Requirement, Postoperative Analgesia Status: Unknown status Trial end date: 2011-12-01 Target enrollment: Participant gender: Summary The investigators hypothesized that valproic acid will increase rocuronium requirement and MgSO4 infusion would reduce requirement of muscle relaxant in craniotomy patients preloaded with sodium valproate. Phase: N/A Details Lead Sponsor: Seoul National University Bundang HospitalTreatments: Magnesium SulfateRocuroniumValproic Acid